This invention relates to a sheet metal drawing equipment, and more particularly to an improvement in a sheet metal drawing equipment which is adapted to permit a recess of a sheet metal which is to be drawn to be suitably drawn through washers welded to the recess.
A conventional sheet metal drawing equipment of such a type is disclosed in Japanese Utility Model Publication No. 27290/1987 (62-27290) and constructed in such a manner as shown in FIGS. 17 to 20, wherein drawing of a recess 250 of a sheet metal is carried out through a fitment 260 welded to a surface of the recess 250.
Unfortunately, the conventional sheet metal drawing equipment has several disadvantages.
More particularly, the sheet metal drawing equipment is so constructed that a support 203 is formed of a single plate material and operation arms 205 each are connected at one end thereof to the support 203. Thus, in order to ensure that the sheet metal drawing equipment effectively carries out various kinds of drawing operations, it is required to form the support 203 into an increased length. Unfortunately, this tends to cause deformation or distortion of the support with progress of operation of the operation arms 205. Such deformation or distortion leads to a failure in operation of the sheet metal drawing equipment.
Also, sheet metal working carried out while contacting surface contact sections 221 of legs 202 with a surface of a sheet metal decreased in stiffness causes depression of a portion of the surface contacted with the contact surface sections 221 of the legs 202 as shown in FIG. 17B, resulting in the recess to be drawn being migrated, for example, from a position indicated at dashed lines 350 in FIG. 18B to that indicated at a solid line 360. In order to avoid such a problem to satisfactorily carry out sheet metal working, it would be effective that the surface contact sections 221 of the legs 202 are placed on a stiff portion 310 of a sheet metal such as a skeleton 310 (FIG. 21) formed by an outer panel 301 of a door 300 of an automobile and an inner panel 302 thereof. However, formation of the support 203 into a length L shown in FIG. 20 fails to ensure that the conventional sheet metal drawing equipment satisfactorily draws not only such a recess at a central portion of a metal sheet as indicated at reference numeral 365 in FIG. 19 but such a recess at an end portion of a metal sheet as indicated at reference numeral 370 in FIG. 20, because a movable rod 215 and the operation arms 205 fail to slide in a longitudinal direction of the support 203 unlike the legs 202. For this purpose, it is required to form the support 203 into a length N (=L+M; N&gt;L) shown in FIG. 20. However, this renders a gravity of the sheet metal drawing equipment unstable and disadvantageously increases a weight thereof, leading to a failure in satisfactory and rapid sheet metal working.